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1 /*
2  * File...........: linux/drivers/s390/block/dasd_diag.c
3  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
4  * Based on.......: linux/drivers/s390/block/mdisk.c
5  * ...............: by Hartmunt Penner <hpenner@de.ibm.com>
6  * Bugreports.to..: <Linux390@de.ibm.com>
7  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999,2000
8  *
9  */
10
11 #define KMSG_COMPONENT "dasd"
12
13 #include <linux/stddef.h>
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
16 #include <linux/hdreg.h>
17 #include <linux/bio.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/jiffies.h>
21
22 #include <asm/dasd.h>
23 #include <asm/debug.h>
24 #include <asm/ebcdic.h>
25 #include <asm/io.h>
26 #include <asm/s390_ext.h>
27 #include <asm/vtoc.h>
28 #include <asm/diag.h>
29
30 #include "dasd_int.h"
31 #include "dasd_diag.h"
32
33 #define PRINTK_HEADER "dasd(diag):"
34
35 MODULE_LICENSE("GPL");
36
37 /* The maximum number of blocks per request (max_blocks) is dependent on the
38  * amount of storage that is available in the static I/O buffer for each
39  * device. Currently each device gets 2 pages. We want to fit two requests
40  * into the available memory so that we can immediately start the next if one
41  * finishes. */
42 #define DIAG_MAX_BLOCKS (((2 * PAGE_SIZE - sizeof(struct dasd_ccw_req) - \
43                            sizeof(struct dasd_diag_req)) / \
44                            sizeof(struct dasd_diag_bio)) / 2)
45 #define DIAG_MAX_RETRIES        32
46 #define DIAG_TIMEOUT            50 * HZ
47
48 static struct dasd_discipline dasd_diag_discipline;
49
50 struct dasd_diag_private {
51         struct dasd_diag_characteristics rdc_data;
52         struct dasd_diag_rw_io iob;
53         struct dasd_diag_init_io iib;
54         blocknum_t pt_block;
55         struct ccw_dev_id dev_id;
56 };
57
58 struct dasd_diag_req {
59         unsigned int block_count;
60         struct dasd_diag_bio bio[0];
61 };
62
63 static const u8 DASD_DIAG_CMS1[] = { 0xc3, 0xd4, 0xe2, 0xf1 };/* EBCDIC CMS1 */
64
65 /* Perform DIAG250 call with block I/O parameter list iob (input and output)
66  * and function code cmd.
67  * In case of an exception return 3. Otherwise return result of bitwise OR of
68  * resulting condition code and DIAG return code. */
69 static inline int dia250(void *iob, int cmd)
70 {
71         register unsigned long reg2 asm ("2") = (unsigned long) iob;
72         typedef union {
73                 struct dasd_diag_init_io init_io;
74                 struct dasd_diag_rw_io rw_io;
75         } addr_type;
76         int rc;
77
78         rc = 3;
79         asm volatile(
80                 "       diag    2,%2,0x250\n"
81                 "0:     ipm     %0\n"
82                 "       srl     %0,28\n"
83                 "       or      %0,3\n"
84                 "1:\n"
85                 EX_TABLE(0b,1b)
86                 : "+d" (rc), "=m" (*(addr_type *) iob)
87                 : "d" (cmd), "d" (reg2), "m" (*(addr_type *) iob)
88                 : "3", "cc");
89         return rc;
90 }
91
92 /* Initialize block I/O to DIAG device using the specified blocksize and
93  * block offset. On success, return zero and set end_block to contain the
94  * number of blocks on the device minus the specified offset. Return non-zero
95  * otherwise. */
96 static inline int
97 mdsk_init_io(struct dasd_device *device, unsigned int blocksize,
98              blocknum_t offset, blocknum_t *end_block)
99 {
100         struct dasd_diag_private *private;
101         struct dasd_diag_init_io *iib;
102         int rc;
103
104         private = (struct dasd_diag_private *) device->private;
105         iib = &private->iib;
106         memset(iib, 0, sizeof (struct dasd_diag_init_io));
107
108         iib->dev_nr = private->dev_id.devno;
109         iib->block_size = blocksize;
110         iib->offset = offset;
111         iib->flaga = DASD_DIAG_FLAGA_DEFAULT;
112
113         rc = dia250(iib, INIT_BIO);
114
115         if ((rc & 3) == 0 && end_block)
116                 *end_block = iib->end_block;
117
118         return rc;
119 }
120
121 /* Remove block I/O environment for device. Return zero on success, non-zero
122  * otherwise. */
123 static inline int
124 mdsk_term_io(struct dasd_device * device)
125 {
126         struct dasd_diag_private *private;
127         struct dasd_diag_init_io *iib;
128         int rc;
129
130         private = (struct dasd_diag_private *) device->private;
131         iib = &private->iib;
132         memset(iib, 0, sizeof (struct dasd_diag_init_io));
133         iib->dev_nr = private->dev_id.devno;
134         rc = dia250(iib, TERM_BIO);
135         return rc;
136 }
137
138 /* Error recovery for failed DIAG requests - try to reestablish the DIAG
139  * environment. */
140 static void
141 dasd_diag_erp(struct dasd_device *device)
142 {
143         int rc;
144
145         mdsk_term_io(device);
146         rc = mdsk_init_io(device, device->block->bp_block, 0, NULL);
147         if (rc == 4) {
148                 if (!(test_and_set_bit(DASD_FLAG_DEVICE_RO, &device->flags)))
149                         pr_warning("%s: The access mode of a DIAG device "
150                                    "changed to read-only\n",
151                                    dev_name(&device->cdev->dev));
152                 rc = 0;
153         }
154         if (rc)
155                 pr_warning("%s: DIAG ERP failed with "
156                             "rc=%d\n", dev_name(&device->cdev->dev), rc);
157 }
158
159 /* Start a given request at the device. Return zero on success, non-zero
160  * otherwise. */
161 static int
162 dasd_start_diag(struct dasd_ccw_req * cqr)
163 {
164         struct dasd_device *device;
165         struct dasd_diag_private *private;
166         struct dasd_diag_req *dreq;
167         int rc;
168
169         device = cqr->startdev;
170         if (cqr->retries < 0) {
171                 DBF_DEV_EVENT(DBF_ERR, device, "DIAG start_IO: request %p "
172                             "- no retry left)", cqr);
173                 cqr->status = DASD_CQR_ERROR;
174                 return -EIO;
175         }
176         private = (struct dasd_diag_private *) device->private;
177         dreq = (struct dasd_diag_req *) cqr->data;
178
179         private->iob.dev_nr = private->dev_id.devno;
180         private->iob.key = 0;
181         private->iob.flags = DASD_DIAG_RWFLAG_ASYNC;
182         private->iob.block_count = dreq->block_count;
183         private->iob.interrupt_params = (addr_t) cqr;
184         private->iob.bio_list = dreq->bio;
185         private->iob.flaga = DASD_DIAG_FLAGA_DEFAULT;
186
187         cqr->startclk = get_clock();
188         cqr->starttime = jiffies;
189         cqr->retries--;
190
191         rc = dia250(&private->iob, RW_BIO);
192         switch (rc) {
193         case 0: /* Synchronous I/O finished successfully */
194                 cqr->stopclk = get_clock();
195                 cqr->status = DASD_CQR_SUCCESS;
196                 /* Indicate to calling function that only a dasd_schedule_bh()
197                    and no timer is needed */
198                 rc = -EACCES;
199                 break;
200         case 8: /* Asynchronous I/O was started */
201                 cqr->status = DASD_CQR_IN_IO;
202                 rc = 0;
203                 break;
204         default: /* Error condition */
205                 cqr->status = DASD_CQR_QUEUED;
206                 DBF_DEV_EVENT(DBF_WARNING, device, "dia250 returned rc=%d", rc);
207                 dasd_diag_erp(device);
208                 rc = -EIO;
209                 break;
210         }
211         cqr->intrc = rc;
212         return rc;
213 }
214
215 /* Terminate given request at the device. */
216 static int
217 dasd_diag_term_IO(struct dasd_ccw_req * cqr)
218 {
219         struct dasd_device *device;
220
221         device = cqr->startdev;
222         mdsk_term_io(device);
223         mdsk_init_io(device, device->block->bp_block, 0, NULL);
224         cqr->status = DASD_CQR_CLEAR_PENDING;
225         cqr->stopclk = get_clock();
226         dasd_schedule_device_bh(device);
227         return 0;
228 }
229
230 /* Handle external interruption. */
231 static void
232 dasd_ext_handler(__u16 code)
233 {
234         struct dasd_ccw_req *cqr, *next;
235         struct dasd_device *device;
236         unsigned long long expires;
237         unsigned long flags;
238         u8 int_code, status;
239         addr_t ip;
240         int rc;
241
242         int_code = *((u8 *) DASD_DIAG_LC_INT_CODE);
243         status = *((u8 *) DASD_DIAG_LC_INT_STATUS);
244         switch (int_code) {
245         case DASD_DIAG_CODE_31BIT:
246                 ip = (addr_t) *((u32 *) DASD_DIAG_LC_INT_PARM_31BIT);
247                 break;
248         case DASD_DIAG_CODE_64BIT:
249                 ip = (addr_t) *((u64 *) DASD_DIAG_LC_INT_PARM_64BIT);
250                 break;
251         default:
252                 return;
253         }
254         if (!ip) {              /* no intparm: unsolicited interrupt */
255                 DBF_EVENT(DBF_NOTICE, "%s", "caught unsolicited "
256                               "interrupt");
257                 return;
258         }
259         cqr = (struct dasd_ccw_req *) ip;
260         device = (struct dasd_device *) cqr->startdev;
261         if (strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
262                 DBF_DEV_EVENT(DBF_WARNING, device,
263                             " magic number of dasd_ccw_req 0x%08X doesn't"
264                             " match discipline 0x%08X",
265                             cqr->magic, *(int *) (&device->discipline->name));
266                 return;
267         }
268
269         /* get irq lock to modify request queue */
270         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
271
272         /* Check for a pending clear operation */
273         if (cqr->status == DASD_CQR_CLEAR_PENDING) {
274                 cqr->status = DASD_CQR_CLEARED;
275                 dasd_device_clear_timer(device);
276                 dasd_schedule_device_bh(device);
277                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
278                 return;
279         }
280
281         cqr->stopclk = get_clock();
282
283         expires = 0;
284         if (status == 0) {
285                 cqr->status = DASD_CQR_SUCCESS;
286                 /* Start first request on queue if possible -> fast_io. */
287                 if (!list_empty(&device->ccw_queue)) {
288                         next = list_entry(device->ccw_queue.next,
289                                           struct dasd_ccw_req, devlist);
290                         if (next->status == DASD_CQR_QUEUED) {
291                                 rc = dasd_start_diag(next);
292                                 if (rc == 0)
293                                         expires = next->expires;
294                         }
295                 }
296         } else {
297                 cqr->status = DASD_CQR_QUEUED;
298                 DBF_DEV_EVENT(DBF_DEBUG, device, "interrupt status for "
299                             "request %p was %d (%d retries left)", cqr, status,
300                             cqr->retries);
301                 dasd_diag_erp(device);
302         }
303
304         if (expires != 0)
305                 dasd_device_set_timer(device, expires);
306         else
307                 dasd_device_clear_timer(device);
308         dasd_schedule_device_bh(device);
309
310         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
311 }
312
313 /* Check whether device can be controlled by DIAG discipline. Return zero on
314  * success, non-zero otherwise. */
315 static int
316 dasd_diag_check_device(struct dasd_device *device)
317 {
318         struct dasd_block *block;
319         struct dasd_diag_private *private;
320         struct dasd_diag_characteristics *rdc_data;
321         struct dasd_diag_bio bio;
322         struct vtoc_cms_label *label;
323         blocknum_t end_block;
324         unsigned int sb, bsize;
325         int rc;
326
327         private = (struct dasd_diag_private *) device->private;
328         if (private == NULL) {
329                 private = kzalloc(sizeof(struct dasd_diag_private),GFP_KERNEL);
330                 if (private == NULL) {
331                         DBF_DEV_EVENT(DBF_WARNING, device, "%s",
332                                 "Allocating memory for private DASD data "
333                                       "failed\n");
334                         return -ENOMEM;
335                 }
336                 ccw_device_get_id(device->cdev, &private->dev_id);
337                 device->private = (void *) private;
338         }
339         block = dasd_alloc_block();
340         if (IS_ERR(block)) {
341                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
342                             "could not allocate dasd block structure");
343                 device->private = NULL;
344                 kfree(private);
345                 return PTR_ERR(block);
346         }
347         device->block = block;
348         block->base = device;
349
350         /* Read Device Characteristics */
351         rdc_data = (void *) &(private->rdc_data);
352         rdc_data->dev_nr = private->dev_id.devno;
353         rdc_data->rdc_len = sizeof (struct dasd_diag_characteristics);
354
355         rc = diag210((struct diag210 *) rdc_data);
356         if (rc) {
357                 DBF_DEV_EVENT(DBF_WARNING, device, "failed to retrieve device "
358                             "information (rc=%d)", rc);
359                 rc = -EOPNOTSUPP;
360                 goto out;
361         }
362
363         /* Figure out position of label block */
364         switch (private->rdc_data.vdev_class) {
365         case DEV_CLASS_FBA:
366                 private->pt_block = 1;
367                 break;
368         case DEV_CLASS_ECKD:
369                 private->pt_block = 2;
370                 break;
371         default:
372                 pr_warning("%s: Device type %d is not supported "
373                            "in DIAG mode\n", dev_name(&device->cdev->dev),
374                            private->rdc_data.vdev_class);
375                 rc = -EOPNOTSUPP;
376                 goto out;
377         }
378
379         DBF_DEV_EVENT(DBF_INFO, device,
380                       "%04X: %04X on real %04X/%02X",
381                       rdc_data->dev_nr,
382                       rdc_data->vdev_type,
383                       rdc_data->rdev_type, rdc_data->rdev_model);
384
385         /* terminate all outstanding operations */
386         mdsk_term_io(device);
387
388         /* figure out blocksize of device */
389         label = (struct vtoc_cms_label *) get_zeroed_page(GFP_KERNEL);
390         if (label == NULL)  {
391                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
392                             "No memory to allocate initialization request");
393                 rc = -ENOMEM;
394                 goto out;
395         }
396         rc = 0;
397         end_block = 0;
398         /* try all sizes - needed for ECKD devices */
399         for (bsize = 512; bsize <= PAGE_SIZE; bsize <<= 1) {
400                 mdsk_init_io(device, bsize, 0, &end_block);
401                 memset(&bio, 0, sizeof (struct dasd_diag_bio));
402                 bio.type = MDSK_READ_REQ;
403                 bio.block_number = private->pt_block + 1;
404                 bio.buffer = label;
405                 memset(&private->iob, 0, sizeof (struct dasd_diag_rw_io));
406                 private->iob.dev_nr = rdc_data->dev_nr;
407                 private->iob.key = 0;
408                 private->iob.flags = 0; /* do synchronous io */
409                 private->iob.block_count = 1;
410                 private->iob.interrupt_params = 0;
411                 private->iob.bio_list = &bio;
412                 private->iob.flaga = DASD_DIAG_FLAGA_DEFAULT;
413                 rc = dia250(&private->iob, RW_BIO);
414                 if (rc == 3) {
415                         pr_warning("%s: A 64-bit DIAG call failed\n",
416                                    dev_name(&device->cdev->dev));
417                         rc = -EOPNOTSUPP;
418                         goto out_label;
419                 }
420                 mdsk_term_io(device);
421                 if (rc == 0)
422                         break;
423         }
424         if (bsize > PAGE_SIZE) {
425                 pr_warning("%s: Accessing the DASD failed because of an "
426                            "incorrect format (rc=%d)\n",
427                            dev_name(&device->cdev->dev), rc);
428                 rc = -EIO;
429                 goto out_label;
430         }
431         /* check for label block */
432         if (memcmp(label->label_id, DASD_DIAG_CMS1,
433                   sizeof(DASD_DIAG_CMS1)) == 0) {
434                 /* get formatted blocksize from label block */
435                 bsize = (unsigned int) label->block_size;
436                 block->blocks = (unsigned long) label->block_count;
437         } else
438                 block->blocks = end_block;
439         block->bp_block = bsize;
440         block->s2b_shift = 0;   /* bits to shift 512 to get a block */
441         for (sb = 512; sb < bsize; sb = sb << 1)
442                 block->s2b_shift++;
443         rc = mdsk_init_io(device, block->bp_block, 0, NULL);
444         if (rc && (rc != 4)) {
445                 pr_warning("%s: DIAG initialization failed with rc=%d\n",
446                            dev_name(&device->cdev->dev), rc);
447                 rc = -EIO;
448         } else {
449                 if (rc == 4)
450                         set_bit(DASD_FLAG_DEVICE_RO, &device->flags);
451                 pr_info("%s: New DASD with %ld byte/block, total size %ld "
452                         "KB%s\n", dev_name(&device->cdev->dev),
453                         (unsigned long) block->bp_block,
454                         (unsigned long) (block->blocks <<
455                                          block->s2b_shift) >> 1,
456                         (rc == 4) ? ", read-only device" : "");
457                 rc = 0;
458         }
459 out_label:
460         free_page((long) label);
461 out:
462         if (rc) {
463                 device->block = NULL;
464                 dasd_free_block(block);
465                 device->private = NULL;
466                 kfree(private);
467         }
468         return rc;
469 }
470
471 /* Fill in virtual disk geometry for device. Return zero on success, non-zero
472  * otherwise. */
473 static int
474 dasd_diag_fill_geometry(struct dasd_block *block, struct hd_geometry *geo)
475 {
476         if (dasd_check_blocksize(block->bp_block) != 0)
477                 return -EINVAL;
478         geo->cylinders = (block->blocks << block->s2b_shift) >> 10;
479         geo->heads = 16;
480         geo->sectors = 128 >> block->s2b_shift;
481         return 0;
482 }
483
484 static dasd_erp_fn_t
485 dasd_diag_erp_action(struct dasd_ccw_req * cqr)
486 {
487         return dasd_default_erp_action;
488 }
489
490 static dasd_erp_fn_t
491 dasd_diag_erp_postaction(struct dasd_ccw_req * cqr)
492 {
493         return dasd_default_erp_postaction;
494 }
495
496 /* Create DASD request from block device request. Return pointer to new
497  * request on success, ERR_PTR otherwise. */
498 static struct dasd_ccw_req *dasd_diag_build_cp(struct dasd_device *memdev,
499                                                struct dasd_block *block,
500                                                struct request *req)
501 {
502         struct dasd_ccw_req *cqr;
503         struct dasd_diag_req *dreq;
504         struct dasd_diag_bio *dbio;
505         struct req_iterator iter;
506         struct bio_vec *bv;
507         char *dst;
508         unsigned int count, datasize;
509         sector_t recid, first_rec, last_rec;
510         unsigned int blksize, off;
511         unsigned char rw_cmd;
512
513         if (rq_data_dir(req) == READ)
514                 rw_cmd = MDSK_READ_REQ;
515         else if (rq_data_dir(req) == WRITE)
516                 rw_cmd = MDSK_WRITE_REQ;
517         else
518                 return ERR_PTR(-EINVAL);
519         blksize = block->bp_block;
520         /* Calculate record id of first and last block. */
521         first_rec = blk_rq_pos(req) >> block->s2b_shift;
522         last_rec =
523                 (blk_rq_pos(req) + blk_rq_sectors(req) - 1) >> block->s2b_shift;
524         /* Check struct bio and count the number of blocks for the request. */
525         count = 0;
526         rq_for_each_segment(bv, req, iter) {
527                 if (bv->bv_len & (blksize - 1))
528                         /* Fba can only do full blocks. */
529                         return ERR_PTR(-EINVAL);
530                 count += bv->bv_len >> (block->s2b_shift + 9);
531         }
532         /* Paranoia. */
533         if (count != last_rec - first_rec + 1)
534                 return ERR_PTR(-EINVAL);
535         /* Build the request */
536         datasize = sizeof(struct dasd_diag_req) +
537                 count*sizeof(struct dasd_diag_bio);
538         cqr = dasd_smalloc_request(DASD_DIAG_MAGIC, 0, datasize, memdev);
539         if (IS_ERR(cqr))
540                 return cqr;
541
542         dreq = (struct dasd_diag_req *) cqr->data;
543         dreq->block_count = count;
544         dbio = dreq->bio;
545         recid = first_rec;
546         rq_for_each_segment(bv, req, iter) {
547                 dst = page_address(bv->bv_page) + bv->bv_offset;
548                 for (off = 0; off < bv->bv_len; off += blksize) {
549                         memset(dbio, 0, sizeof (struct dasd_diag_bio));
550                         dbio->type = rw_cmd;
551                         dbio->block_number = recid + 1;
552                         dbio->buffer = dst;
553                         dbio++;
554                         dst += blksize;
555                         recid++;
556                 }
557         }
558         cqr->retries = DIAG_MAX_RETRIES;
559         cqr->buildclk = get_clock();
560         if (blk_noretry_request(req) ||
561             block->base->features & DASD_FEATURE_FAILFAST)
562                 set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);
563         cqr->startdev = memdev;
564         cqr->memdev = memdev;
565         cqr->block = block;
566         cqr->expires = DIAG_TIMEOUT;
567         cqr->status = DASD_CQR_FILLED;
568         return cqr;
569 }
570
571 /* Release DASD request. Return non-zero if request was successful, zero
572  * otherwise. */
573 static int
574 dasd_diag_free_cp(struct dasd_ccw_req *cqr, struct request *req)
575 {
576         int status;
577
578         status = cqr->status == DASD_CQR_DONE;
579         dasd_sfree_request(cqr, cqr->memdev);
580         return status;
581 }
582
583 static void dasd_diag_handle_terminated_request(struct dasd_ccw_req *cqr)
584 {
585         cqr->status = DASD_CQR_FILLED;
586 };
587
588 /* Fill in IOCTL data for device. */
589 static int
590 dasd_diag_fill_info(struct dasd_device * device,
591                     struct dasd_information2_t * info)
592 {
593         struct dasd_diag_private *private;
594
595         private = (struct dasd_diag_private *) device->private;
596         info->label_block = (unsigned int) private->pt_block;
597         info->FBA_layout = 1;
598         info->format = DASD_FORMAT_LDL;
599         info->characteristics_size = sizeof (struct dasd_diag_characteristics);
600         memcpy(info->characteristics,
601                &((struct dasd_diag_private *) device->private)->rdc_data,
602                sizeof (struct dasd_diag_characteristics));
603         info->confdata_size = 0;
604         return 0;
605 }
606
607 static void
608 dasd_diag_dump_sense(struct dasd_device *device, struct dasd_ccw_req * req,
609                      struct irb *stat)
610 {
611         DBF_DEV_EVENT(DBF_WARNING, device, "%s",
612                     "dump sense not available for DIAG data");
613 }
614
615 static struct dasd_discipline dasd_diag_discipline = {
616         .owner = THIS_MODULE,
617         .name = "DIAG",
618         .ebcname = "DIAG",
619         .max_blocks = DIAG_MAX_BLOCKS,
620         .check_device = dasd_diag_check_device,
621         .fill_geometry = dasd_diag_fill_geometry,
622         .start_IO = dasd_start_diag,
623         .term_IO = dasd_diag_term_IO,
624         .handle_terminated_request = dasd_diag_handle_terminated_request,
625         .erp_action = dasd_diag_erp_action,
626         .erp_postaction = dasd_diag_erp_postaction,
627         .build_cp = dasd_diag_build_cp,
628         .free_cp = dasd_diag_free_cp,
629         .dump_sense = dasd_diag_dump_sense,
630         .fill_info = dasd_diag_fill_info,
631 };
632
633 static int __init
634 dasd_diag_init(void)
635 {
636         if (!MACHINE_IS_VM) {
637                 pr_info("Discipline %s cannot be used without z/VM\n",
638                         dasd_diag_discipline.name);
639                 return -ENODEV;
640         }
641         ASCEBC(dasd_diag_discipline.ebcname, 4);
642
643         ctl_set_bit(0, 9);
644         register_external_interrupt(0x2603, dasd_ext_handler);
645         dasd_diag_discipline_pointer = &dasd_diag_discipline;
646         return 0;
647 }
648
649 static void __exit
650 dasd_diag_cleanup(void)
651 {
652         unregister_external_interrupt(0x2603, dasd_ext_handler);
653         ctl_clear_bit(0, 9);
654         dasd_diag_discipline_pointer = NULL;
655 }
656
657 module_init(dasd_diag_init);
658 module_exit(dasd_diag_cleanup);